It is known that items of retail and wholesale stores may be identified using unique identifiers. These unique identifiers may include, for instance, radio frequency identification (RFID) tags. These RFID tags may be attached to each of the items. On the RFID tags, a unique identification, such as a unique number, may be stored. This number may be interrogated from the unique identifier for taking inventory of the store. The unique identifiers may also be used during purchase of items from the stores. At the checkout desk, the unique identification may be read from the unique identifier and a corresponding price may be provided. This enables a cashier to scan the items quickly and to calculate the price of all items automatically.
To update the inventory of the store, it is also known in the art that if an item is actually sold, this item may be deleted from the list of the items on stock. This may be done, for instance, by using the unique identification, which may be stored in a database. When the item is sold, the database is updated, such that, for instance, the unique identification may be deleted completely from the database. Such items may include, for instance, goods, products, devices, foods, or any other items that may be sold in a store.
However, a technical problem of retail stores, convenience stores, restaurants, wholesale stores or any other stores may be that they do not know whether an item has previously been sold, or, if the item has previously been sold, whether it is allowed to be sold again. For example, a customer may return a previously-purchased item for credit. As another example, a customer may sneak an item into a store and improperly place it for sale.
In particular, maliciously modified items may be brought to a store undiscovered, to be used for blackmailing the store. Manipulated items may be items that have been bought or stolen from the same store, or from somewhere else. For instance, food may be manipulated with poison, and then brought back to the store and placed on the shelves. A customer may not detect the manipulation and may buy this item. There is no technical implementation that prevents items that are not intended to be sold from being taken from the store.
In the example just given, a customer would buy poisoned food. As a result, the store may be sued by the customer, even though the store is not responsible for the poisoning of the customer. Moreover, the original producer of the food item may suffer as well, as its brand or image may be damaged in the marketplace (for example, by negative publicity surrounding the sale of the poisoned food item).
A related technical problem may be that items, which, for example, have been returned or brought unauthorized into a store, need to be detected. It may be necessary to prevent these items from being sold.